The Memcached plugin implements cache interface for memcached.

See: http://memcached.org/

The difference between the former `MemcachePlugin` and `MemcachedPlugin` is that they use,
respectively, `memcache` and `memcached` as the underlying php libraries. These are similar
libraries, made by different authors with slightly different cacpabilities, therefore `memcached`
was selected.

Installation
============

Tell your `config.php` to use this plugin (replace `tcp://localhost:6379` with the address/port
of your Memcache backend server):

`addPlugin('Memcached');`

Note that this typically requires configuring the `memcached` extension for `php`, which is
typically available as a binary package from your system's package manager. In Debian based systems
and on Arch based systems, this is likely available under the `php-memcached` package. Note the
final `d`. On Arch, uncomment the line in `/etc/php/conf.d/memcached.ini` and restart your webserver
and/or php-fpm or similar.

Settings
========

servers: Array of memcached servers addresses. Each server address should be either a string with
address or an array where the first element is a string with the address an optional second element
with the port.

defaultExpiry: How long before cache expires (in seconds)

Example
=======

addPlugin('Memcached', [ 'servers' => ['127.0.0.1', 11211],
                         'defaultExpiry' => 86400 // 24h
                       ]);